Treatment of recycling gas for direct thermochemical conversion of high molecular weight organic substances into low viscosity liquid raw materials, combustibles and fuels

ABSTRACT

The invention relates to a method for the direct thermochemical conversion of high molecular weight organic starting products into low molecular weight organic products that are liquid with a low viscosity at ambient temperature and can be combusted. Said method consists of the following steps: (1) the starting product, at least one reducing gas and slow-evaporating product fractions are provided in a reactor, (2) the provided starting material is rapidly heated to a reaction temperature, (3) said starting material is converted using the temperature, the reducing effect of the gas and autocatalytical effects of the product fractions in vaporous reaction products and reaction gas, (4) the reaction gas is separated by means of condensation by evacuating the condensed reaction products, said separated reaction gas comprising a mixture of hydrogen, methane and other hydrocarbons and carbon monoxide and carbon dioxide. Said claimed method is characterised by other additional steps: (5) the separated reaction gas is conditioned by (a) removing at least one part of the carbon dioxide or (b) reforming at least one part of the carbon dioxide and the methane and/or other hydrocarbons or one part of the methane and/or other hydrocarbons or (c) removing one part of the carbon dioxide and reforming in parallel at least one part of the carbon dioxide and at least one part of the methane and/or other hydrocarbons or (d) removing one part of the carbon dioxide and subsequently reforming at least one other part of the carbon dioxide and at least one part of the methane and/or other hydrocarbons or (e) reforming one part of the carbon dioxide and at least one part of the methane and/or other hydrocarbons and subsequently removing at least one part of the carbon dioxide and optionally, introducing hydrogen, said conditioning followed by (6) re-injecting the conditioned reaction gas into the reactor for simultaneously producing a hydrating, reducing and stripping effect for converting the starting material. According to the invention, the amount of active gas fractions and its part in the total flow of the reaction gas can be modified in an advantageous manner, thus increasing the effectiveness of the method and leading to an improvement of the target product quality and yield with total lower production costs. The invention also relates to a method for carrying out the claimed method.

The invention relates to a method for the direct thermochemical conversion of high molecular weight organic substances into low molecular weight organic products that are liquid with a low viscosity at ambient temperature. Furthermore, the invention relates to a device for carrying out the method according to the invention.

Carbon-containing materials and material mixtures of preferably long-chain or cross-linked molecules are called high molecular weight organic substances, such as occur, especially, in renewable raw materials and in materials from the waste economy, such as, for example, biomass, wood waste, plants, plant oils, animal fats, bone meal, waste oils, plastic waste and effluent sludge. These materials or material mixtures form the preferred starting materials or raw materials for the method according to the invention.

The aimed for low molecular weight products or target products, which are present in the form of low viscosity liquids at ambient temperature and can be combusted, are in particular high-grade, as far as possible pure hydrocarbons, such as petrochemical combustibles and fuels, with only a small heteroatom fraction (oxygen, sulphur, nitrogen, halogens, phosphorus, etc), the intrinsic value of the target products being determined by the hydrocarbon fraction and increasing with it.

Methods for direct thermochemical conversion of high molecular weight organic substances into low molecular weight products and devices suitable for this are known from the prior art. In these methods, also called direct liquefaction, organic solid material macro molecules are cracked or shortened at relatively low temperatures to about 500° C. until the molecule lengths are present in the range of the respectively desired low-viscosity liquid, the so-called product oil, as the target product.

Compared to conventional cracking processes in the vapour phase of a conversion reactor, it has proven accordingly to be especially advantageous if the cracking reactions take place with preheating of the starting materials, optionally including required solid material catalysts, and with intensive intermixing of the reaction components in the sump phase of the reactor. In this case, the preheating temperature depends on the cracking temperature or reaction temperature and is preferably selected to be lower than this.

In combination with this conduct of the method, the reaction mixture is heated by shock heating in the range of seconds to the reaction temperature, which is made possible by the direct provision of the preheated starting materials in crushed form in the sump phase of the reactor and the intensive intermixing.

The poorly volatile product fractions being produced as reaction products in the reactor and the inorganic constituents of the starting materials have an autocatalytic effect, which has an advantageous effect on the reaction parameters of duration, pressure and temperature. The maintenance of the autocatalytic effect while saving additional catalysts is ensured by a return, provided according to the prior art, of these poorly volatile product fractions present as liquid heavy oils to the reactor.

A method of this type is described in the patent application DE-A1-102 15 679, which was carried out with the cooperation of one of the inventors here. According to this, the thermochemical conversion or direct liquefaction of the high molecular weight organic starting materials into the high-grade low molecular weight target products mentioned takes place by a sump phase reaction at temperatures between 350° C. and 500° C. utilising the autocatalytic effects mentioned of the poorly volatile product fractions guided in the circuit and furthermore utilising a selective, product-oriented residence time control, namely with immediate and targeted removal of the cracking products from the reaction zone, as soon as the molecular lengths thereof have reached the area of the desired target product. This selective product-oriented residence time control is realised by the distillation and stripping simultaneously occurring in the reactor at the boiling temperature of the reaction mixture, in that components which can be evaporated or are volatile are removed from the reaction mixture, on the one hand, by means of transition using distillation into the vapour phase and, on the other hand, are transferred from the liquid phase into the gas phase by means of a carrier gas flow.

In the case of starting materials with a lack of hydrogen and/or an increased heteroatom fraction, a hydrogenating and/or reducing gas, preferably hydrogen and/or carbon monoxide as the carrier gas flow, is guided through the liquid phase in the reactor, which is accompanied by a reduction in the reaction gas pressure and by a reduction in the hydrogenating catalyst requirement. The hydrogen is used here to stabilise the cracking products and improve the quality of the product oil. The hydrogenating effect of the hydrogen only occurs, however, at an increased reaction pressure, which is in turn dependent on the starting product. In starting products with a low heteroatom fraction, therefore with a great chemical similarity between the starting material and target product, both the process guidance under excess pressure and the hydrogen component in the reaction gas can be dispensed with. In cases such as this, the thermochemical conversion preferably takes place at a reduced reaction pressure or at negative pressure in the reactor.

The reaction mixture is generally present in the reactor in a gas-vapour phase, a liquid phase and a solid phase. The gas-vapour phase is composed here of the reaction gas and the vaporous reaction products. The reaction gas comprises by-products of the cracking reactions and optionally further components, for example the hydrogenating gas hydrogen. The vaporous reaction products are in the form of evaporated product oil hydrocarbons and—depending on the starting materials used—optionally water vapour. The liquid phase is formed by the poorly volatile product fractions present as heavy oils, while the solid phase, in addition to solid reaction residues, also has added solid material catalysts and non-volatile starting materials.

According to DE-A1-102 15 679, the gas-vapour phase is separated by means of phase separation from the liquid phase with the solid phase suspended therein. This liquid phase is then transferred by further phase separation into the poorly volatile product fractions, which are in turn returned to the reactor. The separated gas-vapour phase is split by means of condensation under reaction pressure into the reaction gas with reducing and hydrogenating fractions and into the vaporous reaction products with condensable oil and water fractions. By separation, in addition to the product gas, product oil, product water and aerosol are obtained in this manner. The hydrogen fraction is isolated by means of gas separation from the reaction gas thus obtained and returned in its entirety to the reactor as hydrogenating gas. The remaining reaction gas fraction is thus necessarily also returned as stripping gas to the reactor and/or used as combustion gas to obtain process energy, optionally after pressure compensation or relief in the case of a process conduct at excess pressure. If the conversion takes place under increased reaction pressure, this also supplies the preliminary pressure required for the gas separation and also contributes to a reduction in the compression energy required to return the hydrogen to the reactor.

Poorly volatile product fractions still present are isolated by distillation from the vaporous reaction products according to the teaching of DE-A1-102 15 679, optionally after pressure relief in the case of a process conduct at excess pressure, said product fractions being in turn returned to the reactor. Owing to the optionally required pressure relief, gas fractions released in the liquid phase are released and are separated following the distillation by means of a further condensation step and used for the process energy supply. The liquid reaction products remaining here only still contain product oil and, depending on the raw material, water. The latter is optionally separated in a further phase separation step, so only the product oil desired as the target product remains.

To obtain additional hydrogen for return to the reactor as hydrogenating gas, synthesis gas with components carbon monoxide and hydrogen is optionally formed from the water separated in this phase separation and from solid fractions of the poorly volatile product fractions returned to the reactor with the addition of external water by means of water vapour gasification according to DE-A1-102 15 679. This is then directly introduced into the reactor as a reducing and hydrogenating gas. Optionally, alternatively or additionally to this, the synthesis gas, also together with the water obtained from the phase separation, in a carbon monoxide conversion, is completely transferred into hydrogen and carbon dioxide. The hydrogen obtained in this manner is then released from the carbon dioxide in a further gas separation process and introduced as the hydrogenating gas component into the reactor. This further gas separation is used to provide hydrogen from the reaction gas to return to the reactor and, by means of the separated reaction gas, to ensure the energy supply of the total thermochemical conversion and/or to also supply this as stripping gas to the reactor.

It is desirable from certain points of view to aim for improvements here. Thus, the reductions of hydrogenating components of the reaction gas required for the thermochemical conversion in the reactor are already fixed with regard to the quantity and composition with the selection of the starting material and therefore not accessible to further adjustment. This has the consequence that an optimal utilisation of the gas fractions contained in the reaction gas is not provided, which has a limiting effect on the efficiency of the method and the quality and yield of the target products and leads to increased method costs.

In addition, the return of the reaction gas to the reactor is directly and exclusively determined by the reaction pressure prevailing there. To this extent, possible pressure fluctuations in the reactor and inside the reaction gas circuit therefore have an effect on the reaction gas feed into the reactor such that the reducing, hydrogenating and stripping effect of the reaction gas in the reactor likewise fluctuates and the aimed for removal of the cracking products from the reaction zone, in other words, the method-specific selective product-oriented residence time control, can be disturbed, so ultimately the quality and yield of the target products decrease. Moreover, the reaction gas guided in the circuit purely caused by the large number of method steps to be run through, is subject to a considerable loss, which leads to a reduction in the efficiency of the method and therefore likewise to a smaller target product yield.

The present invention is based on the object of developing the method which is very advantageous and already described in DE-A1-102 15 679 taking into account the above described facts in such a way that a method conduct is made possible, in which the direct thermochemical conversion of high molecular weight organic starting materials in low molecular weight organic target products takes place with improved quality and a higher yield with overall lower method costs. It is furthermore the object of the invention to disclose a device for carrying out the method according to the invention.

This aim is achieved by a method with the features of claim 1:

The invention is based on the concept of disclosing a method for the direct thermochemical conversion of at least one high molecular weight organic starting material into low molecular weight organic products, which are liquid with a low viscosity at ambient temperature and can be combusted, comprising the method steps:

(1) providing the starting material, poorly volatile product actions and at least one reducing gas in a reactor, (2) shock heating the starting material to the reaction temperature, (3) converting the starting material at elevated temperature using the reduced effect of the gas and/or autocatalytic effects of the product fractions in vaporous reaction products and reaction gas, (4) separating the reaction gas by means of condensation by removing the condensed reaction products, the separated reaction gas a) comprising hydrogen, methane and optionally further hydrocarbon products, carbon monoxide and carbon dioxide in the case of oxygen-containing starting materials and b) comprising hydrogen, methane and optionally further hydrocarbons in the case of oxygen-free starting materials, characterised by the further method steps of (5) conditioning the separated reaction gas by means of

-   -   discharging at least one part of the gas mixture and/or     -   removing at least one part of the carbon dioxide or     -   reforming at least one part of the carbon dioxide, the methane         and/or further hydrocarbons or     -   removing one part of the carbon dioxide and parallel reforming         of at least a further part of the carbon dioxide and at least         one part of the methane and/or further hydrocarbons or     -   removing one part of the carbon dioxide and subsequent reforming         of at least a further part of the carbon dioxide and at least         one part of the methane and/or further hydrocarbons or     -   reforming one part of the carbon dioxide and at least one part         of the methane and/or further hydrocarbons and subsequent         removal of at least one further part of the carbon dioxide and         optionally, additionally by means of the feeding of hydrogen         and/or another reducing material, especially in the form of         carbon monoxide and/or tetralin,         (6) returning the conditioned reaction gas to the reactor to         simultaneously produce a reducing, especially hydrogenating         effect to convert the starting material and/or a stripping         effect to discharge the product.

The alternatively disclosed method steps of conditioning the separated reaction gas in combination with the optional feeding of additional hydrogen therefore allow an adjustment of the components of the reaction gas effective for the method according to the quantity and composition and therefore also an adjustment of the total gas quantity returned to the reactor. Consequently, the simultaneous hydrogenating, reducing and stripping effect of the reaction gas in the reactor during the conversion of the starting materials can be controlled by means of the reaction gas conditioning according to the invention.

The gas conditioning is accordingly carried out in such a way that the hydrogen content of the reaction gas is sufficient to ensure, in the reactor, a hydrogenating atmosphere or the partial hydrogen pressure necessary for the thermochemical conversion. The reducing atmosphere necessary for the oxygen degradation in the conversion reaction in the reactor is provided by the reducing effect of the carbon monoxide, methane and optionally further hydrocarbon components of the conditioned reaction gas and advantageously assisted by the hydrogen component. The stripping effect of the conditioned reaction gas returned to the reactor is ensured by the returned total gas quantity. A possible deficit of hydrogen in the separated reaction gas, which can occur, for example, caused by the starting material, is compensated by means of the additional feeding of hydrogen during the conditioning.

The advantageous effect of the method according to the invention, namely the optimised conversion of the starting material in the reactor with simultaneous cracking, distillation and/or stripping, is therefore produced from the direct sequence of the method steps disclosed individually and is, to this extent, based on the special type of reaction gas guidance or circulating gas treatment.

The conditioning alternative disclosed to achieve the object according to the invention to the separated reaction gas advantageously takes into account the large spectrum of starting products which can be used according to the method. Depending on the respective starting material or the material components of the raw material used, the conditioning alternative is selected, with which an optimal composition of the individual effective reaction components and total gas quantity is to be ensured with regard to the simultaneous hydrogenating, reducing and stripping effect for the conversion of the starting material in the reactor.

The removal of the carbon dioxide from the separated reaction gas or the reduction of the carbon dioxide fraction contained according to the first conditioning alternative may, for example, take place by means of a diaphragm separation process. Carbon monoxide, at least methane and optionally further hydrocarbons and hydrogen remain as the important components in the reaction gas thus being produced, so the quantity of the effective gas fractions and the fraction thereof of the total flow are advantageously increased.

During the reforming of the carbon dioxide and the methane and/or the further hydrocarbons disclosed as the second conditioning alternative, these components of the reaction gas are converted into carbon monoxide and hydrogen, so the fraction thereof in the total gas flow and the quantity of the effective gas fractions are still further increased compared to the first method alternative. A conversion of this type may, for example, take place in fixed bed reactors on platinum catalysts.

A still greater adjustability or optimisation of the effective gas fractions and their fraction in the total gas flow, therefore a further increase in quality of the reaction gas, is possible by combining the first two method alternatives.

According to the third conditioning alternative, the reaction gas separated during the condensation is subjected in two parallel method steps to a carbon dioxide removal and a reforming of the carbon dioxide, methane and/or the further hydrocarbons.

According to the fourth conditioning alternative, the removal of the carbon dioxide fraction firstly takes place in a first method step and immediately following this, the reforming of the separated reaction gas and optionally then still present carbon dioxide fractions and the fractions of methane and further hydrocarbons takes place in a second method step.

A serial sequence of the method steps also has the fifth conditioning alternative, according to which, however, the reforming of the fractions present in the reaction gas of carbon dioxide, methane and/or further hydrocarbons takes place as the first method step and immediately thereafter in a second method step, the removal of the optionally still present carbon dioxide fractions takes place.

Each conditioning alternative also comprises the feeding of hydrogen, to be carried out if necessary, into the separated reaction gas. This feeding preferably takes place immediately following the carbon dioxide removal and/or the reforming of the carbon dioxide, the methane and/or the further hydrocarbons.

According to the method of the invention, the quantity of the effective gas fractions and the fraction thereof in the total flow of the reaction gas can therefore be modified in an advantageous manner. Compared to the method known from DE-A1-102 15 679, the optimisation thus possible in the utilisation of the gas fractions obtained in the reaction gas leads to an increase in the efficiency of the method and to an improvement in the target product quality and yield with overall lower method costs.

The further hydrocarbon may, for example, be ethane, propane and/or butane without being limited thereto. The poorly volatile product fractions may comprise hydrocarbons with at least 18 carbon atoms, preferably with 20 to 40 carbon atoms. The boiling point at atmospheric pressure may preferably be between 350° C. and 500° C.

Further advantageous embodiments of the method according to the invention emerge from the dependant claims 2 to 16 and are described below:

In the method of the invention, carbon-containing materials and/or material mixtures of long-chain and/or cross-linked macro molecules, especially in the form of renewable raw materials as well as residual and waste materials, are advantageously used as the starting materials. These include, especially, biomass, wood waste, plants, plant oils, animal fats, bone meal, used oils, plastics material waste and effluent sludge.

In view of the quality and yield of the target products, it is especially advantageous if the starting material and the reaction gas are provided in the liquid heavy oil phase of the reactor gas. However, provision of the reaction components in the vapour phase of the reactor is basically also possible.

The reaction temperatures and reaction pressures which are optimal for the thermochemical conversion depend on the respective starting materials. For the conversion of the raw materials preferably used in the method according to the invention into the preferred target products, namely product oils, reaction temperatures of 200° C. to 600° C., especially 300° C. to 500° C., at absolute reaction pressures of 0.1 bar to 300 bar, especially from 0.5 bar to 200 bar, are preferably required. Especially, it is advantageous in the preferred starting materials with elevated oxygen, sulphur or nitrogen fractions, if a reducing excess pressure atmosphere prevails during the conversion in the reactor. This is preferably formed by the feeding of reducing gases such as, for example, carbon monoxide and/or hydrogen at elevated pressure to about 200 bar.

To stabilise the method conduct, the starting materials are continuously fed to the reactor and the vaporous reaction products and the reaction gas are expediently continuously removed from the reactor.

The vapour phase removed continuously from the reactor and liquefied by condensation forms the condensed reaction products removed from the reaction gas circuit with the petrochemical combustibles and fuels preferred as the target products with a high hydrocarbon content and low viscosity. Liquid heavy oil fractions and reaction water still present are optionally separated by distillation, condensation and/or phase separation by a further treatment of the condensed reaction products according to the prior art.

The conditioned reaction gas is expediently compressed before its return to the reactor. Compressing the reaction gas ensures that possible pressure fluctuations in the reactor or pressure losses within the reaction gas circuit are compensated and therefore the reaction gas feed into the reactor is decoupled from the reaction pressure prevailing therein, so the simultaneous reducing, hydrogenating and stripping effect of the reaction gas in the reactor can be constantly maintained. This ensures that the targeted removal of the crack products from the reaction zone, in other words the method-specific selective, product-oriented residence time control can proceed undisturbed, and in that to this extent, quality and yield fluctuations in the target products are avoided.

Moreover, the compression of the reaction gas also has a stabilising effect in a process conduct under excess pressure, such as is necessary, for example, in the case of the conversion of starting products with a shortage of hydrogen and/or with an increased heteroatom fraction. In this case, it is especially advantageous with regard to the quality and yield of the target product if the reducing excess pressure atmosphere is formed by hydrogen and/or carbon monoxide.

In a preferred embodiment of the invention, condensed reaction products removed from the reaction gas circuit are converted to hydrogen, which is then in turn mixed as a hydrogenating gas fraction with the reaction gas, to control the hydrogenating effect of the reaction gas in the reactor. This return preferably takes place during the compression of the reaction gas.

In the case of a hydrogen excess in the reaction gas circuit, the hydrogen thus obtained can either be temporarily stored or supplied for an external use.

In a further preferred embodiment of the invention, the conditioned reaction gas is preheated before its return to the reactor. A method step of this type supplements the preheating of the starting materials known from the prior art before the feeding thereof into the reactor and further advantageously shortens the heating period of the reaction mixture in the reactor. The aforementioned compression of the conditioned reaction gas expediently takes place before the heating thereof.

As the reaction gas conditioning, supplemented by compression and preheating, requires no further method steps, the total number of method steps forming the reaction circuit is significantly smaller that in the prior art. Accordingly, the loss of reaction gas during the method conduct is substantially smaller than is the case in the closest prior art, which, in comparison, leads to an improvement in efficiency and ultimately to lower method costs.

In a further advantageous development of the method according to the invention, the conditioned reaction gas is used for the pneumatic feeding of starting materials into the reactor. In this case, the crushed and preheated starting materials present as solid materials in a known manner are introduced by means of the reaction gas under excess pressure, in particular directly into the sump phase of the reactor, with intensive intermixing of all the reaction components. It is likewise possible for one part of the conditioned reaction gas flow for the pneumatic feeding of starting materials to be branched off in a targeted manner as a partial gas flow and used in parallel with the main gas flow as a carrier gas for the feeding of starting materials into the reactor.

In addition to this, a further advantageous method conduct comprises in that the reaction gas is used as an inertisation gas for the starting materials in the reactor to improve the quality of the target products. The air oxygen present in the reactor and/or gases capable of reaction or explosion or gas mixtures are thus displaced by the reaction gas.

In a further embodiment of the invention, with a surprisingly advantageous effect on the target product quality and yield, the carbon dioxide fraction present in the reaction gas is at least partially removed from the reaction gas circuit to increase the partial hydrogen pressure in the reactor. This proves to be advantageous, especially if sufficient reaction gas for the stripping effect is present in the reactor. It may also be necessary here for additional carbon dioxide to be isolated by suitable separation from the reaction gas in order to be able to be likewise discharged from the reaction gas circuit. This separation may, for example, take place by gas washes, such as pressure water washes (absorption method with water or alkaline washing agents) or pressure change absorption on activated carbon.

An advantageous embodiment of the method according to the invention also comprises in that the carbon dioxide and methane and further hydrocarbon fractions present in the separated and/or conditioned reaction gas have to be removed from the reaction circuit in order to be used as the reaction media for reforming for synthesis gas production.

In a last embodiment of the method according to the invention, the separated and/or conditioned reaction gas is partly removed from the reaction gas circuit and used to cover the thermal energy requirement during the conversion of the starting material, so a significant improvement in efficiency of the method is made possible.

The aim of the invention is further achieved by a device with the features of claim 16.

The invention is based on the concept of disclosing a device, having a reaction gas circuit to guide gaseous reaction products with at least

-   -   One reactor for carrying out thermochemical conversion reactions         of a reaction mixture in the reactor,     -   a means for liquefying vaporous reaction products,     -   a means for separating liquid reaction products and reaction         gas,         characterised in that furthermore     -   means for conditioning the separated reaction gas to adjust a         reducing, in especially hydrogenating and/or stripping effect of         the reaction gas are provided in the reactor, comprising         -   means for discharging one part of the gas mixture and/or         -   means for removing carbon dioxide or         -   means for reforming carbon dioxide, methane and optionally             further hydrocarbons or         -   means for removing carbon dioxide and means for reforming             carbon dioxide, methane and optionally further hydrocarbons             in a parallel arrangement or         -   means for reforming carbon dioxide, methane and/or further             hydrocarbons as well as, arranged upstream thereof in the             flow direction in the reaction gas circuit, means for             removing carbon dioxide or         -   means for removing carbon dioxide as well as, arranged             upstream thereof in the flow direction in the reaction gas             circuit, means for reforming carbon dioxide, methane and/or             further hydrocarbons and     -   optionally additionally arranged upstream or downstream thereof         in the flow direction in the reaction gas circuit, means for         feeding hydrogen and/or another reducing material.

Advantageous configurations of the device according to the invention emerge from the dependent claims 17 and 18.

The invention will be described with more details below, by way of example, with reference to the accompanying schematic figures, in which:

FIG. 1 shows a flow diagram of a preferred embodiment of the device according to the invention with means for removing carbon dioxide and means for reforming carbon dioxide, methane and further hydrocarbons in a parallel arrangement according to a method alternative and

FIG. 2 shows a flow diagram of a further preferred embodiment of the device according to the invention with means for removing carbon dioxide and means for reforming carbon dioxide, methane and further hydrocarbons in an arrangement connected one behind the other according to a further method alternative.

FIG. 1 shows a schematic view of the arrangement in principle of the device components of a preferred embodiment of the invention and the flow course of the reaction gas during operation of this device. Accordingly, the reaction products produced during the thermochemical conversion of the starting material are removed in the form of hot vapours of gases from the reactor 1 and supplied to a condenser 2 to liquefy the vaporous reaction products with cooling. In a downstream separator 3, the liquid reaction products are separated from the reaction gas. The separated liquid reaction products are separated from the reaction gas circuit and transferred in further treatment stages (not shown) into the target products (product oil). The separated reaction gas, which is now present as a dry mixture and substantially comprises the components carbon dioxide, carbon monoxide, methane, further hydrocarbons (for example ethane, propane or butane) and hydrogen, is now fed, in a first stage, for gas conditioning, having the carbon dioxide removal 4 and, in parallel with this, the reformer 5 for carbon dioxide, methane and further hydrocarbons in order to remove carbon dioxide or convert it to hydrogen and carbon monoxide. The reaction gas leaving the first conditioning stage now also substantially has the components carbon monoxide, methane and further hydrocarbons and hydrogen. The reaction gas thus conditioned is fed to a second stage of gas conditioning, which has the compression 6 and a hydrogen supply to feed additional hydrogen into the reaction gas circuit. In a subsequent third conditioning stage, the modified and compressed reaction gas is heated in gas preheating 7 and then returned directly to the reactor 1.

The invention will be further described below with the aid of application examples:

EXAMPLE 1

A loop reactor (volume=100 l) is filled with a poorly volatile oil, preloaded with a gas mixture of 65 vol. % H₂, 20 vol. % CO and 15 vol. % CH₄ to a pressure of 100 bar and heated to a reaction temperature of 500° C.

The starting materials preheated to 200° C. are continuously metered by means of a suitable feed system into the hot oil of the reactor with a mass flow of 50 kg/h plus 10% water content. As a result, a shock heating of the starting materials which is advantageous for the reaction is achieved. In parallel with the starting material addition, a reaction gas flow at a volume flow of 75 Nm³/h is guided through the reactor, composition: 65 vol. % H₂, 20 vol. % CO and 15 vol. % CH₄.

Owing to the ideal intermixing of the two reaction phases, gas and starting material, in the catalytically acting, poorly volatile reaction oil, the starting materials are converted into vapours and gases which, owing to the stripping effect of the reaction gas flow, are continuously discharged therewith. The gases and vapours leaving the reactor have a temperature of 500° C. and a pressure of 100 bar, the volume flow is 100 Nm³/h with a composition: 20 vol. % H₂, 30 vol. % CO₂, 15 vol. % CO, 10 vol. % CH₄ and 20 vol. % water, 3 vol. % diesel and 2 vol. % petrol vapour.

This flow is cooled to 20° C. in a downstream condenser, which is designed as a pipe coil condenser. The components water, diesel and petrol condense and are separated in a subsequent gravity separator under 100 bar pressure from the gas phase. The liquid phase is relieved of pressure and supplied for a further use.

The gas phase is supplied to a high pressure washing column (packed column, D=150 mm, H=2.5 m): under 100 bar pressure, the gas (75 Nm³/h) is introduced from below and water (m=500 kg/h) is trickled from above as a washing liquid in a counter-flow. The waste water is regenerated by pressure relief and then again used for CO₂ absorption. The fresh water consumption in this concept is about 5 to 10% of the washing water flow.

The cleaned gas flow (45 Nm³/h) still contains negligible traces of CO₂ and substantially 42 vol. % H₂, 33 vol. % CO and 25 vol. % CH₄. This gas flow is compressed by means of a piston compressor with the addition of 30 Nm³/h H₂ to 110 bar and, preheated in a pipe coil heat exchanger to 300° C., guided back into the reactor, where the latter is again available as a reaction gas with a composition of 65 vol. % H₂, 20 vol. % CO and 15 vol. % CH₄ and for stripping the reaction products.

This modification of the circulating gas treatment is a simple concept in terms of apparatus. In order to keep the stripping gas volume flow and the partial hydrogen pressure constant. H₂ is additionally fed in.

EXAMPLE 2

A loop reactor (volume=100 l) is filled with a poorly volatile oil, preloaded with a gas mixture of 53 vol. % H₂ and 47 vol. % CO to a pressure of 80 bar and heated to a reaction temperature of 450° C.

The starting materials preheated to 200° C. are metered continuously by means of a suitable feed system into the hot oil of the reactor at a mass flow of 50 kg/h plus 10% water content. As a result, a shock heating of the starting materials that is advantageous for the reaction is achieved. In parallel with the starting material addition, a reaction gas flow with a volume flow of 78 Nm³/h is guided through the reactor, composition: 53 vol. % H₂ and 47 vol. % CO.

Owing to the ideal intermixing of the two reaction phases, gas and starting material, in the catalytically acting, poorly volatile reaction oil, the starting materials are converted into vapours and gases, which are continuously discharged by the stripping effect of the reaction gas flow with the latter. The gases and vapours leaving the reactor have a temperature of 450° C. and a pressure of 80 bar and the volume flow is 100 Nm³/h with a composition: 20 vol. % H₂, 30 vol. % CO₂, 15 vol. % CO, 10 vol. % CH₄ and 20 vol. % water, 3 vol. % diesel and 2 vol. % petrol vapour.

This gas/vapour flow is relieved to 2 bar by means of a gas expansion turbine, so the mixture is cooled to 350° C. The expansion work of the gas is converted into mechanical work here, which is removed as shaft power.

The mixture thus relieved is broken down in a conventional distillation column at atmospheric pressure into its fractions water, petrol, diesel and gas. The liquid fractions are removed as products for further use, while the gas flow (75 Nm³/h), composition: 25 vol. % H₂, 40 vol. % CO₂, 20 vol. % CO and 15 vol. % CH₄ is guided into a reformer. The components CO₂ and CH₄ of the reaction gas are selectively converted on a fixed bed reactor with the aid of a platinum catalyst at 600° C. to CO and H₂. The CH₄ is converted here almost completely according to the reaction equation, see Example 2. After the reforming process, the gas is cooled, and the volume flow is now 97.5 Nm³/h with a composition of 42 vol. % H₂, 20 vol. % CO and 38 vol. % CO.

This gas flow is compressed by means of a piston compressor to 90 bar and supplied to a high pressure washing column (packed column, D=200 mm, H=2.5 m): under 90 bar pressure, the gas (97.5 Nm³/h) is introduced from below and water (m=380 kg/h) is trickled from above as washing liquid in a counter-flow. The waste water is regenerated by pressure relief and can then be used again for CO₂ absorption. The fresh water consumption in this concept is about 5 to 10% of the washing water flow.

The cleaned gas flow (78 Nm³/h) still contains negligible traces of CO₂ and substantially 53 vol. % H₂ and 47 vol. % CO.

This is preheated to 400° C. in a pipe coil heat exchanger. The hot gas flow is guided back into the reactor, where the latter is again available as a reaction gas with a composition of 53 vol. % H₂ and 47 vol. % CO and is available for the stripping of the reaction products.

Especially advantageous here are the obtaining of energy from the compressed gases, the production of finished products in the form of petrol and diesel and the operation of the process that is self sufficient in hydrogen.

LIST OF REFERENCE NUMERALS

-   1 Reactor -   2 Condenser -   3 Separator -   4 Carbon dioxide removal -   5 Reformer for carbon dioxide, methane and further hydrocarbons -   6 Compression -   7 Gas preheating 

1. A method for the direct thermochemical conversion of at least one high molecular weight organic starting material into low molecular weight organic products, which are liquid with a low viscosity at ambient temperature and can be combusted, comprising the method steps: providing the starting material, poorly volatile product fractions and at least one reducing gas in a reactor, shock heating the starting material to the reaction temperature, converting the starting material at elevated temperature using the reducing effect of the gas and/or autocatalytic effects of the product fractions in vaporous reaction products and reaction gas, separating the reaction gas by means of condensation by removing the condensed reaction products, the separated reaction gas a) comprising hydrogen, methane and optionally further hydrocarbon products, carbon monoxide and carbon dioxide in the case of oxygen-containing starting materials and b) comprising hydrogen, methane and optionally further hydrocarbons in the case of oxygen-free starting materials, characterised by the further method steps of conditioning the separated reaction gas by means of discharging at least one part of the gas mixture and/or removing at least one part of the carbon dioxide or reforming at least one part of the carbon dioxide, the methane and/or further hydrocarbons or removing one part of the carbon dioxide and parallel reforming of at least a further part of the carbon dioxide and at least one part of the methane and/or further hydrocarbons or removing one part of the carbon dioxide and subsequent reforming of at least a further part of the carbon dioxide and at least one part of the methane and/or further hydrocarbons or reforming one part of the carbon dioxide and at least one part of the methane and/or further hydrocarbons and subsequent removal of at least one further part of the carbon dioxide and optionally, additionally by means of the feeding of hydrogen and/or another reducing material, especially in the form of carbon monoxide or tetralin, returning the conditioned reaction gas to the reactor to simultaneously produce a reducing, especially hydrogenating effect to convert the starting material and/or a stripping effect to discharge the product.
 2. A method according to claim 1, characterised in that the oxygen-containing and/or oxygen-free starting materials contain further heteroatoms in the form of nitrogen, sulphur and/or halogens, which are at least partly removed in the form of ammonia, hydrogen sulphide and/or hydrogen halide.
 3. A method according to claim 1, characterised in that carbon-containing materials and/or material mixtures of long-chained and/or cross-linked macro molecules, especially in the form of renewable raw materials and residual and waste materials, are used as the starting materials.
 4. A method according to claim 1, characterised in that the starting material and the reaction gas are provided in a liquid, poorly volatile product fraction and/or in the vapour phase of the reactor.
 5. A method according to claim 1, characterised in that the starting material is converted in the reactor at a reaction temperature of 200° C. to 600° C.
 6. A method according to claim 1, characterised in that the starting material is converted in the reactor at an absolute reaction pressure of 0.1 bar to 300 bar.
 7. A method according to claim 1, characterised in that the starting material is converted in the reactor in a reducing pressure atmosphere of 20 to 250 bar.
 8. A method according to claim 1, characterised in that the vaporous reaction products and the reaction gas are continuously removed from the reactor.
 9. A method according to claim 1, characterised in that the starting materials are continuously supplied to the reactor.
 10. A method according to claim 1, characterised in that petrochemical raw materials, combustibles and fuels with a high hydrocarbon fraction and low viscosity are obtained from the condensed reaction products removed from the reaction gas circuit.
 11. A method according to claim 1, characterised in that the conditioned reaction gas is returned to the reactor in a compressed state.
 12. A method according to claim 1, characterised in that hydrogen for feeding into the reaction gas circuit is obtained from the condensed reaction products removed from the reaction gas circuit.
 13. A method according to claim 11, characterised in that the hydrogen, during the compression of the reaction gas, is returned to the reaction gas circuit.
 14. A method according to claim 1, characterised in that the conditioned reaction gas is returned to the reactor in a preheated state.
 15. A method according to claim 1, characterised in that the conditioned reaction gas is used for pneumatic feeding of the starting material into the reactor.
 16. A device for carrying out the method according to claim 1, having a reaction gas circuit for guiding gaseous reaction products with at least one reactor (1) for carrying out thermochemical conversion reactions of a reaction mixture in the reactor, a means (2) for liquefying vaporous reaction products, a means (3) for separating liquid reaction products and reaction gas, characterised in that furthermore means for conditioning the separated reaction gas (4, 5) to adjust a reducing, especially hydrogenating and/or stripping effect of the reaction gas are provided in the reactor, comprising means for discharging one part of the gas mixture and/or means for removing carbon dioxide (4) or means for reforming carbon dioxide, methane and/or further hydrocarbons (5) or means for removing carbon dioxide (4) and means for reforming carbon dioxide, methane and/or further hydrocarbons (5) in a parallel arrangement or means for reforming carbon dioxide, methane and/or further hydrocarbons (5) as well as, arranged upstream thereof in the flow direction in the reaction gas circuit, means for removing carbon dioxide (4) or means for removing carbon dioxide (4), as well as, arranged upstream thereof in the flow direction in the reaction gas circuit, means for reforming carbon dioxide, methane and/or further hydrocarbons (5) and optionally, additionally arranged upstream or downstream thereof in the flow direction in the reaction gas circuit, means for feeding hydrogen and/or another reducing material.
 17. A device according to claim 16, characterised in that the reaction gas circuit is high pressure-stable and has means for heating the gas.
 18. A device according to claim 16, characterised in that compression means (6) are provided to compensate pressure losses in the reaction gas circuit.
 19. A method according to claim 1, characterised in that the starting material is converted in the reactor at a reaction temperature of 300° C. to 500° C.
 20. A method according to claim 1, characterised in that the starting material is converted in the reactor at an absolute reaction pressure of 1 bar to 250 bar. 